<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
  <link rel="stylesheet" href="3.css">
</head>
<body>
<!--需求1：分别定义两个 div、span标签，分别修改每个 div 标签的样式为：边框1个像素，实线，红色。-->
<div id="div">div标签1</div>
<div>div标签2</div>
<span class="span">span标签1</span>
<span>span标签2</span>
<a href="../html/表格标签.html">表格</a>
<iframe src="1-css.html"></iframe>
</body>
</html>
